Management implications and options for a stock with unstable or uncertain dynamics: West of Scotland herring

Abstract

An evaluation of the stock-recruitment relationship for west of Scotland herring indicates that the models fitting the data from different periods deviate substantially. The different perceptions of the population dynamics processes emerging from these relationships lead to a range of potential scenarios for future development of the stock. Optimized strategic choices vary between exploitation at fishing mortality (F) of 0.25 and 0.45, with substantial differences in long-term yield depending primarily on the validity of the underlying stock-recruitment relationship. A detailed evaluation of the consequences for management in the short, medium and long term is presented. The uncertainty in stock dynamics and the strategic options are discussed along with the consequences for potential yield caused by the choice between management options. The study includes an evaluation showing that it may take at least ten years of exploitation at reduced yield before the current uncertainties about stock productivity might be resolved. © 2007 International Council for the Exploration of the Sea. Published by Oxford Journals. All rights reserved.